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1973-1987 GM K Series Cummins Conversion Kit | GF-GMK3-KIT


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Product Description

Our 73-87 GM Truck K Series Cummins Kit is comprised of many of the items needed for your Cummins diesel engine conversion. It includes a transmission adapter and flexplate to mate a TH400, 700R4, or 4L80E transmission to a 6BT Cummins engine.  Our Cummins bolt-in 2" drop engine crossmember (or K Member) allows for proper engine placement and provides chassis strength to accommodate the added torque of the Cummins!

  • Fits Truck Model Years: 73-87.
  • Fits Engine Years: 89-02.
  • Fits Transmissions: Chevrolet TH400, 700R4, 4L80E.
  • This kit is comprised of some of our most popular items for your 73-87 Chevy K Series Cummins conversion.
  • The Kit includes:
    • GF-C-S - Adapter and Flexplate-  The 5.9 Cummins to Chevy Adapter Plate and Flexplate Kit accommodates 2002 and earlier Cummins 6BT engines bolting to a Chevy automatic transmission such as a TH400, 700R4, 4L80E, or similar transmission.
    • GF-GMDC - Cummins 6BT to Chevy Drop Crossmember-  This 2" drop crossmember allows proper engine placement and often eliminates the need for a lift kit when installing a Cummins 6BT into a 73-87 Chevy 4WD truck.
    • GF-C-MM - Motor Mount- When installing a Cummins 6BT into your 1973-1987 Chevy pickup, this conversion motor mount allows for proper placement of the engine directly to the OEM frame mount isolators. When used in conjunction with a G Force GF-GMDC Drop Crossmember on 4WD models, you can retain OEM drivetrain height. Without our GF-GMDC Drop Crossmember a vehicle body lift is required.
    • GF-BoltKitAdapter - Adapter Bolt Kit,  Premium grade bellhousing adapter bolt kits to make mounting the adapter plate to engine as simple as possible. Set of 9 bolts.
    • GF-BoltKitFP - Flexplate Bolt Kit, -Flexplate bolts for mounting your Cummins 6BT to a GM Bellhousing. 12mm x 1.25. 25mm underhead length. Set of 8 bolts
    • GF-BoltKitStarter - Starter Bolt Kit - Steel, zinc plated bolts constructed to strict engineering quality standards and serve as direct replacement bolts for replacing the Cummins 6BT starter. Set of 4 bolts with 3 washers

Note: This kit ships in two boxes.

The G Force Patented Transmission Crossmember

Performance Engineered from Start to Finish


Our engineers are also car enthusiasts—which makes designing automotive parts second nature. Because we use our products, we know the importance of crafting them with strength and durability. Get more performance from G Force.

Easy Installation.
It’s Foolproof!

We engineer bold solutions that make installation easier without sacrificing quality. Get more support from G Force.


We packaged all the items you need for our Cummins to GM K Series swap in a convenient kit.

Best of all, when you purchase these parts as a kit, we've discounted the price.

You can find out more about a Cummins swap in these blog articles.
Which 6BT Cummins is Best for Your Swap
Diesel Cummins Conversion
The Popular Ford Cummins Swap
Cummins Allison>


1973 | 1974 | 1975 | 1976 | 1977 | 1978 | 1979 | 1980 | 1981 | 1982 | 1983 | 1984 | 1985 | 1986 | 1987


TH400 | 700R4 | 4L80E



This product ships in 2 boxes.

Weight: 32 lbs
Shipping Dimensions: 21 X 18 X 5 In

Weight: 20 lbs
Shipping Dimensions: 28 X 11 X 7 in

Mounting Hardware: Included

Customer Reviews

Based on 1 review
Cleve Lamey

looks good

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